Firefox 141 for developers

This article provides information about the changes in Firefox 141 that affect developers. Firefox 141 is the current Beta version of Firefox and ships on July 22, 2025.

Note: The release notes for this Firefox version are still a work in progress. You can view the project tracker for this release here.

Changes for web developers

HTML

The HTML webkitdirectory attribute and the corresponding HTMLInputElement.webkitdirectory property are now supported on Firefox Android. The attribute can be set to indicate that an <input type="file"> element should offer selection of directories instead of files. (Firefox bug 1887878).

HTTP

The "cache" directive of the Clear-Site-Data response header now clears the bfcache (backwards-forwards cache). This allows a site to ensure that if anyone navigates backward after a user has signed out, private details that were visible during the initial session will not be exposed. (Firefox bug 1930501).

Changes for add-on developers

Adds the i18n.getPreferredSystemLanguages method to retrieve the preferred locales of the operating system. This complements i18n.getAcceptLanguages which return details of the locales set in the browser. (Firefox bug 1888486)

These features are shipping in Firefox 141 but are disabled by default. To experiment with them, search for the appropriate preference on the about:config page and set it to true. You can find more such features on the Experimental features page.